Electrical receptacle



Feb. 11, 1947. D. N. INGWERSEN ELECTRICAL RECEPTAGLE Filed Nov. 22, 1944 2 Sheets-Sheet 1 v Ewe/z Z07.- flared/d N. frzywer5en, j Z52 M f #1624,

Feb. 11, 1947. D, N .NGWERSEN 2,415,496

ELECTRICAL REGEPTACL'E Filed Nov. 22, 1944 2 Sheets-Sheet 2 .7935: n Z1 g. 6: 7

E22. I F 23 YZ gun f? I Patented Feb. ii, 194? ELECTRICAL RECEPTACLE Donald N. Ingwersen, Chicago, 111., assignor to Sola Electric 00., Chicago, 111., a corporation of Delaware Application November 22, 1944, Serial No. 564,650

Claims. 1

This invention relates to an electrical receptacle and more particularly to a receptacle intended for use with lamps of the tubular type operable at relatively high voltages.

The invention is particularly applicable to the so-called cold cathode lamp which is a development combining certain features of the luminous type of lamp with the more recent fluorescent lamp. Such lamps may be connected for energization in various types of circuits but it will be apprehended from what follows that the invention is equally applicable to receptacles for single lamps or to two or more lamps connected in series, in parallel, in series-parallel, or in separate circuits.

Certain types of luminous tubes of the type just described usually are operated at voltages within a range of from approximately 600 volts to approximately 1000 volts and for that reason such units are classed as high voltage equipment. Accordingly, when used for lighting purposes it is essential that some means be provided to prevent a person handling the lamps from being accidentally subjected to a severe electric shock. Suitably high voltage, as referred to, is generally derived by inserting a step-up transformer inthe usual mains, e. g., 110 volts A. C. or 220 volts A. C., and feeding the lamp from the secondary side at the required voltage, for example, 600 to 1000 volts, depending upon the size of the lamp and its characteristics. The transformer may be of the type having separate primary and secondary windings or it may be of the auto-transformer type, for example, as shown and described in United States Letters Patent No. 2,346,621, granted on April 11, 1944, to Joseph G. Sola.

When a lamp is withdrawn from its receptacles for cleaning or replacement, safety measures dictate that some means must be provided for interrupting the circuit feeding the primary of the transformer, and preferably such means should be automatic in operation, that is to say, the interruption should be without the necessity of conscious thought in that direction by the worker and should occur prior to or simultaneously with the withdrawal of a lamp from its receptacles. In that manner the receptacles and their appurtenant parts are rendered electrically dead and the operator may do whatever is necessary on and about the lamps with perfect safety.

Tubular lamps of the type for which the invention is particularly adapted are usually provided with a prong at each end for making contact with the receptacle, and the description to follow will include as preferred embodiments two types of receptacle for a lamp having a single prong of thin, flat form. However it will be understood that the invention is equally applicable to other forms of prong and even to lamps having a plurality of prongs at each end thereof.

With the foregoing in view, the principal object of my invention is to provide a receptacle in which one end of a tubular lamp may be received and supported during its normal operation, and so adapted that upon the withdrawal of a lamp the circuit supplying current thereto is automatically interrupted, i. e., without the need of any separate operation by the attendant, for example, the opening of a line switch.

, Because of the fact that in practice it is common to connect a unit of lamps, for example, two thereof in parallel to an auto-transformer individual to such pair, I attain the desired object of breaking the circuit in the receptacle by connecting the latter in such manner that current flows from one side of the main line through contacts within the receptacle and then returned to that side of the line, and further by arranging said contacts in such manner that the prong on the lamp serves to complete the circuit within the receptacle,

Accordingly, an additional object is to provide a receptacle having means to receive a prong on the end of the lamp and so arranged that when the lamp is inserted in the two receptacles provided therefor it is secured against accidental dislodgement, as by vibration, while securing an effective contact between the prong on the end of the lamp and the contact or contacts within the receptacle.

Still another object is to provide a. receptacle of the type described having a member to engage the prong on the end of the lamp so formed and arranged that the prong may be engaged therewith by a simple manual movement not requiring the use of tools.

A further object is to provide circuit-breaking means within the receptacle which may be operated by manual pressure on a button, the said operation breaking the circuit established within the receptacle and simultaneously releasing the lamp for withdrawal.

Inasmuch as a lamp of the tubular type requires a receptacle at each end for proper support and admission of current thereto and, furthermore, since the circuit-breaking function need be performed by only one of the two receptacles, it is desirable to simplify manufacturing problems by making the two diflerent receptacles as nearly alike as possible.

For that reason another object is to provide two different constructions of receptacle, similar in function in some respects, so adapted and arranged as to employ certain parts in common. Thus the manufacture of an unnecessary multiplicity of diflerent parts is successfully avoided and the cost of the article correspondingly reduced.

with the above and other objects which will appear hereinafter in view, I have described and shown in the appended drawings one preferred embodiment of each of the two types of receptacles comprising the invention.

In the drawings:

Fig. 1 is an isometric diagrammatic view of a typical circuit and assembly pertinent to a pair of lamps connected in parallel;

Fig. 2 is a rear elevational view of one form of receptacle with the cover removed to reveal the parts therein;

Fig. 3 is a cross sectional view on the line 3-3 of Fig. 2;

Fig. 4 is a plan view of the receptacle shown in Fig. 2;

Fig. 5 shows a rear elevational view of the other form of receptacle with the cover removed;

Fig. 6 is a plan view of the receptacle shown in Fig. 5;

Fig. 7 is a fragmentary view of the prong-contacting and retaining members of the embodiment of Fig. 2 with certain parts omitted for clarity; and

Fig. 8 is a view looking in the direction of the line 8-8 of Fig. 5.

Adverting first to Fig. 1, there are shown at H) two tubular lamps of the type to which the invention is adapted. These comprise the usual cylindrical glass envelope ll including the necessary cathode and gases for the glow discharge and coated on its inner surface with a suitable phosphor to yield the desired fluorescence. Affixed to each end of the lamp H) by a suitable basing compound are the caps l2 of cupped formation each provided with an axially extending prong l3 centrally disposed with respect thereto. Although the prongs I3 are shown as of relatively thin, fiat form, it will be comprehended that these may be of circular or other transverse cross section. As will appear, the essence of the invention to be disclosed herein will be equally adaptable to lamps having prong of types other than that depicted, only certain changes in the dimensions or proportions of the receptacle being necessary to accommodate the same.

Two similar types of receptacles will be described, one for one end of the lamp for simple reception thereof and current supply thereto, and the other associated with the opposite end of the lamp not only for those purposes but to break the circuit feeding the transformer as aforesaid. The first-mentioned type will sometimes for convenience be referred to herein as the singlecontact receptacle and the other as the doublecontact receptacle.

In Fig. 2 I have shown a view of the doublecontact receptacle with the back cover removed. This comprises a box-like casing l9 of electrical insulating material, e. g., molded plastic composition and having a body 20 comprising a thin front wall 2!, thin edge walls 22 and 23 and a thin substantially semi-circular bottom wall 24. Surmounting the body is the mounting portion 25 which is of relatively thicker cross section than the walls and extends beyond the body 20 proper, as more clearly shown in Fig. 4, to form a mounting projection 28. The projection 28 is provided with a central U-shaped slot 21, by means of which the receptacle is properly aligned on the lamp mounting in the usual manner, and with a pair of holes 28 for receiving the bolts by which the receptacle is supported. If desired, the mounting portion 25 may overhang the body 20, as shown at 95, whereby the receptacle may be inserted through a rectangular hole in the lamp support, as is well known in connection with sockets for fluorescent lamps generally.

Carried in a suitably shaped aperture 30 in the mounting portion 25 is the combined contact and retaining member or tongue 3| of relatively thin, narrow cross-section and of resilient material, for example, phosphor bronze or beryllium copper, comprising a straight shank portion 32 widened near its upper extremity and bent upon itself, as at 33, to form 9, lug having a threaded aperture 34 for the reception of the terminal screw 35. It will be noted that the terminal screw is received in an undercut portion 36 of the base 25 in order that the terminal screw and wire connected thereunder may not project beyond the upper surface of the base, thereby permitting the necessary flush condition for mounting of the receptacle. Toward its lower end, the tongue 3! is curved slightly outwardly, as at 4|, and then returned, as at 42, to form a knee 43. It is bent further beyond the knee into an upward inclination 44 to form an acute angle and then back also at an angle to the axis of the tongue to form a cam surface 45 terminating in a tail 45. I

It will be noted that the axis of the tongue 32 is substantially coincident with the vertical center line of the body 20 and that beginning substantially opposite the bend 4| there is provided a slot 5i cut into both the front wall 2| and the bottom wall 24. The entering portion of the slot 5|, i. e., where cut into the bottom wall 24, is tapered outwardly, as indicated at 52, to facilitate the entry of the prong l3 into the receptacle.

Outstanding from the edge walls 22 and 23 and extending into the interior of the receptacle are the two integrally formed projections 55 and 55 (Figs. '2 and 3). The projection 55 is provided on its under-surface with a recess 51 adapted to receive the upwardly bent terminus 5B of the resilient contact member 6| of thin, relatively narrow cross section and comprises a substantially semi-circular lower portion 62, a straight shank 63 and a, suitably formed upper end 55, provided with a threaded aperture 66 for the reception of the other terminal screw 61. Apertures 1| and I2 serve the tongue 6! in the same manner as the corresponding elements 30 and 36 described in connection with the tongue 3|. The usual washers 40 are provided underneath the terminal screws 35 and 51.

Opposite to, and in alignment with, the tongue 6| is the resilient member '15, also substantially semi-circular in form and provided with two ears 15 adapted to be received in apertures 11 in the projection 55.

At this point it will be understood from the foregoing and particularly from Figs. 2 and 3 that the tongues 32 and 6! as well as the member 75 are preferably of the same material and of relatively thin, narrow cross section not only for economy in manufacture but to support the lamp and yield the required resiliency consistent with the pressure necessary for appropriate electrical contact.

Slidably supported in an aperture 8| passing through an integral lug 82 in the wall 2| and also in an aperture 84 in the wall 22 is the button 83 of electrical insulating material. The button 83 may be cylindrical, or of other suitable form, and extends a short distance externally of the casing I9, At its inner end the button 83 is adapted to abut the shank 32 of the tongue 3|. After assembly of the button 83 with the receptacle a pin 85 may be driven therethrough to retain the same against accidental dislod-gment.

To conceal and protect the working parts of the receptacle there is provided a cover 9| (Fig. 4) received within the walls 22, 23 and 24 and retained in position by escutcheon pins 92. The latter may be driven into holes 93 formed in lugs 94 integrally formed with the walls 22 and 23 and in a like hole formed in the mounting portion 25.

The other form of the invention, namely, the single-contact type is depicted in Figs. 5, 6 and 8 and parts similar to those described in connection with the first embodiment are given like reference numerals. It will be noted that the essential difference between the two embodiments is the ommission in the single-contact type of the tongue 6|, member I5, button 83 and their associated supports.

As employed in connection with a lamp of the type illustrated in Fig. l, the invention would function as follows:

Assuming that the receptacles are mounted on the lamp housing by means of bolts passed through the openings 28 so that a single-contact receptacle is disposed at one end of a lamp and a double-contact receptacle at the opposite end and positioned with the slots 5| facing each other for proper reception of the prongs I3, a lamp would be installed by raising it vertically so that the prongs I3 enter the slots 52 and 5| individual to each receptacle. These prongs will first engage the camming portion 45 of the tongue 32 individual to each receptacle and displace it to one side (Fig. 5), Further movement upwardly will cause the prongs I3 to pass beyond the corner where portion 44 meets portion 45, whereupon the tongues 3| are, due to their inherent resilience, permitted to spring back to substantially their normal position to carry the portion 44 underneath the lower edge of the prong I3 (Fig. 7). When such engagement has been made it will be noted that the portions 44 effectively maintain the lamp in the desired vertical position and the knee 43 makes efiective additional contact with one side face of the prong I3.

At the same time a further engagement takes place, but only in connection with the doublecontact receptacle, namely, the prong I3 is wedged between the curved portion 62 of tongue GI and the correspondingly curved member I5 (Fig. '7). As a result of this last-described engagement the prong I3 will form an electrical circuit between the tongues 3| and BI, most clearly seen in Fig. 1.

Referring to that figure, it will be noted that one side of the main line is connected through conductor I00 to the primary winding |0I of the auto-transformer I02, for example of the type shown and described in U. S. Patent No. 2,346,621 hereinbefore referred to. The other side of the mains is connected through a conductor I03 to a tongue 3| of one double-contact receptacle, thence through the associated prong I3 to the ondary winding tongue 6| of that receptacle. The circuit is continued through a conductor I04 to the tongue 8| of the adjacent double-receptacle, through the pron-g I3 engaged therewith and the tongue 3|, through a conductor I05 leading to the other side of the primary IOI of the transformer. One secondary winding I06 of the transformer is connected through a conductor I08 to a condenser I09 and thence through a conductor 0 to the tongue 3| of the single-contact receptacle at the other end of the left-hand lamp. The other sec- II2 is similarly connected through a condenser I 09 and conductor I I3 to the tongue 32 of the remaining single-contact receptacle.

Assuming that the lamps are in position, a circuit may be traced from conductor I00 through the primary IOI through the conductor I05, tongue 3|, prong I3, tongue 6|, conductor I04, tongue 8 I, prong I3, tongue 3|, and conductor I03 to the mains. Thus the primary of the transformer will receive current and since the secondary windings I06 and H2 are connected in autotransformer relation with the primary winding with their respective end terminals connected to the two single-contact receptacles through the conductors H0 and II3, .and the double-contact receptacles are connected to the primary IOI, each of the lamps is energized from one of the secondary windings as disclosed particularly in Fig. 4 of said Patent No. 2,346,621.

To remove a lamp, the button 83 is pushed inwardly of the casing and against the tongue 3|. This actuates the hooked portion 44 from beneath the prong I3 (Fig. '7) and the lamp may be removed by lowering that end thereof individual to the double-contact receptacle. Then, when the prong I3 is cleared outside of the slot 52 the lamp may be moved in the direction of its axis to withdraw the other prong I3 endWise through the slot 5| associated with the single-contact receptacle.

It will be noted that upon operation of the button 83 the knee 43 and hook 44 are separated from their contact with the prong I3 so that the circuit feeding the lamp is effectively interrupted before removal of the lamp is possible. Alternately, removal of the other lamp I0 will interrupt the circuit in the same manner. Thus, upon removal of either or both lamps the circuit to the transformer is completely interrupted and the lamp system is rendered completely safe.

Although the body of the two types of receptacles comprising my invention may be formed of various materials, I prefer, in accordance with modern practice; to mold them of plastic material having high electrical insulating properties.

Under such method of manufacture it is possible to insert the tongues 3| and 6| in the mold and to cause the plastic material to be molded therearound, or these may, as shown, be inserted in suitable apertures forming during the molding operation. A similar expedient may be employed in connection with the tongue BI and member I5 where they engage the projections 55 and 56, respectively. In that event the recesses 51 and TI need not be molded separately.

It will be comprehended that the members 6| and I5 may be combined into a single member appropriately formed to include two arcuate oppositely disposed resilient surfaces between which the prong I3 may be engaged.

While I have shown particular embodiments of my invention, it will be understood, of course,

that I do not wish to be limited thereto since many modifications may be made, and I, thereiore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A receptacle for an electrical device of the type having a prong to engage the receptacle, said prong being adapted to interrupt thev circuit supplying current thereto when disengaged from said receptacle comprising in combination a body portion; a first contact member including a yieldable shank supported at one end on the said body portion, a hooked portion, and a cam portion angularly disposed with respect to said. shank; a second contact member ofiset from said first contact member longitudinally of said prongs and including a yieldable prong engaging protuberance, said cam portion being adapted for camming action with respect to the prong upon insertion of the device in the receptacle, said hooked portion being adapted to receive and retain the prong and to make electrical contact therewith, and said protuberance being adapted to form an electrical contact with the prong, whereby the prong forms an electrical path between said members separate from the electrical path through said device.

2. A receptacle for an electrical device of the type having a prong to engage the receptacle, said prong being adapted to interrupt the circuit supplying current thereto when the device is withdrawn from the receptacle comprising in combination a body portion, a first contact member including a yieldable shank supported at one end on said body portion, a cam portion angularly disposed with respect to said shank, and a prong engaging portion intermediate said end and said cam portion, said prong engaging portion being constituted by deforming said member into an acutely angled ofiset, a second contact member offset from said first contact member longitudinally oi said prongs and including a shank portion and a resilient prong engaging portion, said prong engaging portions of both members being adapted to form an electrical path with said prong in addition to the electric path through said device upon insertion shank portion and a resilient prong engaging portion, said prong engaging portions on said members being oflset longitudinally of said prong to form an electrical path with said prong independent of the circuit through said device upon insertion of the device in the receptacle, said members being electrically insulated one from another, and a slot in at least one wall of the body portion to guide the prong into engagement with the said members.

4. A receptacle for an electrical device oi. the type having a prong to engage the receptacle comprising in combination an enclosed hollow body, a resilient contact tongue insulatedly associated with said body, said tongue including a shank portion for supporting said tongue with respect to said body portion, 'a knee-like portion, a hacked portion and a cam-surface portion.

- said body having a slot in one side, said slot being substantially in lateral alignment with said tongue, a second contact member insulatedly associated with said body and offset longitudinally of said prong from said tongue, said member including a shank portion for supporting said member and an arcuate prong-engaging portion, whereby upon insertion of the prong in the receptacle the prong will strike said cam-suriace comprising in combination a body portion of of the device in the receptacle, and said members being electrically insulated one from another.

3. A receptacle for an electrical device of the type having a prong to engage the receptacle, said electrically non-conductive material, a contact tongue resiliently mounted on said casing, said tongue including a. hooked portion to engage and retain the prong, a pair of resilient, arouately formed contact members electrically insulated from said tongue and supported on said casing, said members being adapted to receive the prong therebetween, and an electrically in:- sulated element movable with respect to said casing and adapted to abut said tongue, said element being adapted upon movement thereof to actuate said tongue and release the prong from said tongue.

DONALD N. INGWERSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,282,875 Mueller May 12, 1942 2,374,032 Mueller Apr. 1'7, 1945 2,241,065 Hawkins May 6, 1941 FOREIGN PATENTS Number Country Date 543,112 British 1942 

